Paraffin cutter



March 2, 1965 I. L. AULT PARAFFIN CUTTER 2 Sheets-Sheet 1 Filed Nov. 8, 1962 F|G.l

FIG. 2b

FIG. 20

o W T mu W VU mm A TTORNEYAZ 2 Sheets-Sheet 2 Filed Nov. 8, 1962 FIG. 4

FIG. 3b

FIG. 30

SEE FIG. 30

INVENTOR. ISAAC L. AULT WMJAM SEE he. 3b k ATTORNEYS.

United States Patent 3,171,487 PARAFFIN CUTTER Isaac lL. Ault, PA). Box 482, Patterson, La. Filed Nov. 8, 1962, Ser. No. 236,223 8 Claims. (Cl. 166-65) The present invention relates generally to oil wells, and more particularly, to a system for cleaning paraffin deposits from the bore of the tubing of an oil well.

In the operation of oil Wells, it has been found that parafiin and other asphaltic or bituminous compounds tend to collect on the bore of the tubing within the well. This accumulation builds up gradually until it seriously restricts the flow of the well, and sometimes entirely clogs it. When either of these conditions arise, it becomes necessary to pull the tubing from the well and clean it of the accumulation of paraffin by steaming or some other suitable manner. This operation takes considerable time and is expensive, not only from the standpoint of labor costs but the delay in obtaining production from the well until the tubing has been cleaned and rerun into the well.

The present invention is designed to remove the accumulation of paraflin in the tubing by providing a system including a device that is continuously and automatically operated.

It is an object of the invention to produce a system for automatically removing parafiin deposits from the bore of oil well tubing which is continuous and automatic in its operation.

Another object of the invention is to produce a system for removing paraflin deposits from the bore of oil well tubing which may operate on a predetermined cycle.

Still a further object of the invention is to produce a device for removing paraflin from the bore of oil well tubing which includes relatively few moving parts and may be readily and economically manufactured.

Other objects and advantages of the invention will be apparent from the following detailed description of a preferred embodiment of the invention when considered in the light of the accompanying drawings, in which:

FIG. 1 is an elevational view partly in section of an oil well equipped with a paraflin cutting tool in accordance with the invention;

FIG. 2a is a fragmentary elevational view partially in section showing the upper portion of the paraflin cutter device and showing the relative position of the elements thereof for effecting a downward movement of the device within an associated well tubing;

FIG. 2b is a fragmentary elevational view in section of the lower portion of the device illustrated in FIG. 2a;

FIG. 3a is a fragmentary elevational view partially in section of the upper portion of the cutter device showing the relative position of the elements thereof for effecting an upward movement of the device within an associated well tubing;

FIG. 3b is a fragmentary elevational view in section of the lower portion of the device illustrated in FIG. 3a; and

FIG. 4 is a fragmentary sectional elevational view of the upper end of the well tubing and showing the mechanism for holding the paraffin cutter in its uppermost position.

Referring to FIG. 1, there is shown a well casing 14 through which a well tubing 12 extends. As is well known, the annular space or zone between the casing and the tubing 12 is sealed off by suitable packing means within the casing head 14. The well fluids which are being produced flow upwardly through the well tubing 12 and are discharged therefrom to an outlet line 16 which has suitable control valving mounted therein, not specifically shown. Paraflin accumulation occurs, in gen- "ice eral, at the upper portion of the well tubing 12 where the temperature is low enough to cause it to precipitate from the oil. Most of the accumulation occurs during periods when the well is not producing as, for example, during the period of shutdown in a prorated area, at which time wax tends to precipitate from the oil in the tubing. Manifestly, this tends to diminish the flow of the oil through the tubing and, in certain instances, may entirely cut off the flow. In order to militate against undue and unwanted accumulation of paraffin in the well tubing 12, the paraflin cutter 18 is automatically and periodically caused to be dropped into the well tubing 12 from an electromagnet 20 maintained or suspended within an upper receiver housing 22. The cutter 18 is of such a structure, as will be explained in detail hereinafter, that it will fall downwardly through the tubing 12 until it contacts a stop member 24 which is perforated to permit the passage of oil therethrough. Upon contacting the stop member 24, the cutter 18 closes the ports therein, causing the well pressure to carry the cutter upwardly in the tubing 12. During the ascent, the cutter scrapes the paraflin accumulation off the side of the tubing.

The receiver housing 22 is provided with a flow line by-pass 19 which is necessary to induce fluid flow up into the receiver. The other end of the flow line by-pass 19 is connected to the outlet 16.

The momentum of the cutter 18 is sufiicient to propel the cutter into the receiver housing 22 and to cause it to come into contact with the electromagnet 20. The electromagnet 219 is provided with a cavity 21 adapted to receive the uppermost end of the cutter 18. Assuming the electromagnet 2i) is placed in an energized condition, the cutter 18 will be suitably held thereby for the period of time in which the electromagnet 20 is energized. The electromagnet 20 is suspended within the receiver housing 22 by a flexible pressure chamber 26 formed of rubber, for example. An electrical insulating sleeve 23 is disposed about the outer peripheral surface of the electromagnet 20 to effectively insulate the magnet from the receiver housing 22. The pressure chamber 26 is charged to a predetermined pressure and is maintained at a desired pressure by inserting pressure fluid through an associated line 28 and serves as a buffer or impact dampener to cushion the electromagnet 20 when impacted by the cutter 18 which has been propelled by the fluid pressure within the well tubing.

Referring to FIGS. 2a and 2b, there is a detailed illustration of the cutter 18 which comprises an outer cylindrical sleeve 31 and a cooperating inner sleeve 32. The inner sleeve 32 is adapted to slide within the outer sleeve 31 between limits determined by a pin 34 in the outer sleeve and cooperating slots 36 and 38 formed in the inner sleeve 32. It will be noted that the lower portion of the outer sleeve 30 is provided with a plurality of ports 40; while the inner sleeve is provided with a plurality of ports 42. The spacing between the ports 40 and 42 in their respective sleeve element is the same such that when the inner and the outer sleeve elements are in the position shown in F168. 2a and 2b, the ports are in alignment. With the ports 40 and 42 in alignment, fluid may thereby flow through the cutter, allowing the cutter to fall within the tube casing 12.

Near the top portion of the inner sleeve 32 there is disposed a pair of similar O-rings 44 which are preferably disposed in annular grooves formed in the outer surface of the sleeve 32. At the opposite end of the inner sleeve. there is disposed another pair of O-rings 46 which are disposed in suitable annular channels or grooves formed in the outer surface of the inner sleeve 32. Slightly below the lowermost port member 42 in the inner sleeve 32, there is disposed an O-ring 48 positioned in an annular groove formed in the outer surface of the inner sleeve 32. The O-rings 44, 46, and 48 act to provide a fluid-tight seal between the inner surface of the outer sleeve 30'a1'1d Outer surface of the inner sleeve Disposed within an elongate bore in the-upper end of l the outer sleeve element SO-there is slidingly disposed a sliding member, generally indicated at 50, which comprises a fishing neck 52 formed of amagne'tiZabIe ma terial, an upper shock block 54, a lower shock block 56, and an intermediate portion 58. The intermediate portion 58 is adapted to slide within the elongate bore hole of the outer sleeve -between the limits defined by the upper and lower shock blocks'54 and 55, respect is provided with a plurality of radially extending iin members 64 which may 'be welded to the base of the outer sleeve 30 or otherwise formed thereontoicontrolthe cutter wobble and reduce wear on an annular cup member 66, as will be described in detail hereinafter.

The lower end vof the outer sleeve '30 is internally threadedito receive an externally threaded member" 68 which is adapted to carry two spaced annular cup members 66;; A cup retainer nut 70' is afiixed to the lower externally threaded portion of the member 68.

The lower face of the cup retainer nut" 70 is formed to mate withthe upper surface 72 of the enlarged lower v portion of the inner cylindrical sleeve element 32.

'At the upper end of the outer sleeve assembly there is V disposed a sleeve member 76 which carries a plurality of radiallyfiextending helically-arranged cutting knife energized condition.

7 4- that since the helices 'of the cutting knife 78 and the cutting knife 80 are reverse with respect to one another,

. the cutter 18 is prevented from spinning and travels along the axis of the Well tubing 12. On its upward path, the

7 cutting knives 7 8 and 80 scrape off and carry any parafiin wllich has, adheredtoth'e'inner' surface of'the well tubing 12. I V a As the cutter 13 reaches the receiver-chamber defined bythe housing 22, the fishing neck 52 is received within the cavity 21 'formed inthe bottom of the electromagnet 22. The upper shock blockv54 contacts and is stopped by thelower surface of'the electroinagnet 22 which positively stops the inner sleeve 32. The momentum of the outer sleeve '30 causes it to travel upwardly 'until it reaches the position shown i'n FIGS. 2a and 2b, in which position the spring biased detent 62 engages Within the V-shaped slot 60', maintaining the'inner and outer sleeves in such relation that the ports and 42 align with one'anothers v v v V a Thecutter 18 is maintained or held in the receiver housing 22 so long as the electromagnet 20 is in a'n Electromagnetic energy is supplied to the magnet20'from'the output of a controllable timed power supply 84 through a-suitable electrical conductor 86. The conductor fidpasses through the top Wall'of [the receiver housing22 within a suitable pressure-tight fitting 88, through the interi or 'of the chamber 26 and finally is coupled to an electrical connector 96, in electrical contact with the electrOmagnet-ZQ,

considered will dictate the duty cycleof the abovedescribed system. For-examplefifthe' frequency of the portions 78 and 80. It will be understood that the I a helix of the cutting knife17$ is opposite to that of the cutting knife 89. The sleeve member 76 is" held in position by'a set screw 77 which is threadedly engaged within the outer sleeve 30. The set screw 77, in addition to being effective in maintaining the sleeve member 76,

The cutting knives 78 and 80 have spaces, as at 82,

' which act as by-passes for the'flow of fluid as the cutter travels in the well tubingr12r h In operation, it will be appreciated that if the ,electro-,

'is also efiective in retaining the springtbiased detent'52f,

duty cycle is once in eachtWenty-four hour period, the power supply 84 will "be turned' otf by suitable timing 'inechanisms, such as a'clock, for approximately five' min utes every twenty-fourhours f Thiswill cause the cutter 18 tom released from theelectromagnet 2t} and travel down the well tubing? 12. When'the ciit'ter *ls r'eturris to the receiver housing 22, the electromagnet 2%, being 'in an energized condition, will be effective to hold the cutter for; another predetermined period According to the patent statutes, I'have explained the principles and mode of operationofmyinvention, and have illustrated and described what I now consider to represent its best embodimenti- However, I desire to have it understood that, withinthe scope of the appended claims, the invention may be practiced otherwise than magnet 20 is de-energized allowing thefishing neck to be released, the cutter 18 will readily' fall downwardly 'withinthe well tubing 12. :The downward flow of the,

cutter 18 is facilitated by the fact'that'the, outer and inner sleeves 30 and 32, respectively, are positioned relative to one another as illustrated in FIGS; Zaand 2b; In this relative positiongthe ports 40" and 42 arein alignpass therethrough thereby militating against an undue pressure build-up within the interior of the. cutter. When the cutter 18 reachcs the stop member 24, the

base 74 of the inner'sleev'e 32 contacts the stop 24 and the momentum of the outer sleeve 36 is suflicient ,to overcome .the force of the detent 62 causing the outer sleeve to travel downwardly in FIGS. 3w and 3b. v v

When they outer sleeve 30 moves. downwardly with respect to the inner s1eeve 32, theirespectiverports 40 'ment allowing the fluid within the well tubing '12 to as sp ecifically illustrated and described.

V I'claim: V I v -1. Asystem for removing paraffin from oil wells including a'parafiin cutter assembly having amagntizable end' portion and adapted to perio'dically drop-within the 7 oil well'to' a predetermined positionf and' their rise to its original position at theupperend of, the oil well, electro- 'magnetic means capable of pro cl'ucinga' magnetic field mounted on'theupper end of the oil well adapted to re- 'ceive said magnjetizable end portion of said cutter as-- f "sembly, and means for periodically automatically deto the position illustrated and T42 move to a position of non-alignment] Thus, I

fluid passage through thecutter 18 is effectively prevented by the plurality of O-rings 144, 46, and'48. 'The fluid pressure within the well tubing 12 will' now act on the cutter 18 and specifically on the;annularlcup"elements, 66 causing the. cutter to rise in thetu'bingi The fins "64 'controhandhelp to eliminatedany wobble of the cutter by stabili'zingits:travel and thereby prevent undue "wear on the cup elements 66; 'Also, it'will be appreciated j energizing said electromagnetic means rpermitting I said cutter assemblyto, be released from said electromagnetic means and drop 'inisaid oil well and for thereafter energizing said electromagnetic means to produce a 'magnetic field and enable said magnetizab'le end portion of said cutter assembly upon its return to the upper ei d of the oil .Well to be'secured-to said el ectromagnetic means.

2. The-invention defined in claim 1 wherein said cutter assembly comprises an outer; cylindrical sleeve, radially extending cutters mounted on the outer surface of said sleevevand adapted torernove paraffin deposits which accumulate on the inner surface of the oil .Well tubing,

' annular cup ring means disposed near one end of said f'sleeve and adapted to provide snug sliding engagement Cil- with the iirteriorjsurface of the oil well, port means ,providing communication through 'saidgsleeve, and an inner' smemb er slidable between a first and a second position The individual conditions of {the particular'well being 5 within said sleeve, said inner member provided with port means adapted to align with the port means in said sleeve when said inner member is in the first position and out of alignment when said inner member is in the second posi tion.

3. The invention defined in claim 2 wherein said magnetizable end portion of said cutter assembly is slidable between a first and a second position within said sleeve, the distance between the first and second position of said end portion being the same as the distance between the first and second position of said inner member.

4. The invention defined in claim 3 wherein said end portion is provided with a pair of spaced apart shock blocks, one of said blocks being positioned within said sleeve and the other of said blocks being positioned outside of said sleeve.

5. The invention defined in claim 2 wherein fin means are attached to the outer surface of said sleeve to stabilize the movement of said assembly within the oil well.

6. The invention defined in claim 1 wherein said electromagnetic means is mounted on the upper end and the top of said oil well by a shock absorbing means.

7. The invention defined in claim 6 wherein said shock absorbing means comprises an inflatable chamber.

8. The invention defined in claim 7 wherein said inflatable chamber is formed of a flexible material for containing a pressure fluid.

References Cited by the Examiner UNITED STATES PATENTS 1,989,035 1/35 Blum 166170 2,267,902 12/41 Eddins 10352 2,695,673 11/54 Coyle 166170 2,829,915 4/58 C'laveau 267188 2,893,493 7/59 Copas 166-170 3,031,971 5/62 Roach 103-52 CHARLES E. OCONNELL, Primary Examiner. 

1. A SYSTEM FOR REMOVING PARAFFIN FROM OIL WELLS INCLUDING A PARAFFIN CUTTER ASSEMBLY HAVING A MAGNETIZABLE END PORTION AND ADAPTED TO PERIODICALLY DROP WITHIN THE OIL WELL TO A PREDETERMINED POSITION AND THEN RISE TO ITS ORIGINAL POSITION AT THE UPPER END OF THE OIL WELL, ELECTROMAGNETIC MEANS CAPABLE OF PRODUCING A MAGNETIC FIELD MOUNTED ON THE UPPER END OF THE OIL WELL ADAPTED TO RECEIVE SAID MAGNETIZABLE END PORTION OF SAID CUTTER ASSEMBLY, AND MEANS FOR PERIODICALLY AUTOMATICALLY DE- 